Torsional vibration suppressor



May 23, 1939. J. M. TYLER r-:r A1.

TOHSIONAL VIBRATION SUPPRESSOR Filed April 4, 1934 2 Sheets-Sheet l May 23, S1939- J. M. TYLER er AL TORSIONL VIBRTION SUPPRESSOR Filed April 4, 1934 2 Sheets-Shawn? 25 tached damper, on the line 2-2- of Fig. 3; two metallic members 24 and 32 of the balancer 25 PatentedMay 23, 1939 j y i lum'rieziz STAT-Es PATENT OFFICE 2,159,235 'roasroNAL vmRATroN surrnpsson John M. Tyler, Birmingham, and Thomas 0. van Degrlft, Detroit, Mich., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application April 4, 1934, Serial No. 718,950 8 Claims. (Cl. 74-574) This invention relates to devices for suppressvented from rearward movement by washer 25 ing or minimizing torsional vibrations in engine seated against a shoulder on the shaft. cranhhafts and the like. The vibration damper is composed of two prin- The principal object of the invention is to cipal metallic members concentrically disposed.

vdampen and balance out torsional vibrations by The inner member consists of a hollow member an inertia body secured to one end of a crank- 24 provided with an annular internal flange 26 v shaft by means of a mass of elastic rubber in between its ends and with an internal longisuch manner as to take full advantage of the tudinal groove 28 to receive the key 22 when said elasticity and high internal friction of rubber. member 24 is fitted over an end of the crank 'I'his and other objects are attained by an asshaft.v Said member 24 is provided with a series 10 sembly of concentrically disposed metallic memof external radiating blade-like elements 30 forbers and a inass of interposed rubber, associated ward of the internal flange 26. with means for adjustably compressing the rub- The outer member 32 of the vibration damper ber, adapted to be secured `to the front end of is a relatively heavy body of adequate inertia an engine crankshaft by the so-called starter which may be grooved to receive the fan driving 15 nut. The vibration suppressing device for conbeit I 9 and the front end of which is hollowed venience is herein specifically named a vibration out and formed witn radially inward projecting damper. v blades 33 intercalated with and spaced in a Fig. 1 is a conventional illustration 'of an autocircumferential sense from the blades 3U when mobile engine crankshaft having at its front end the two members of the balancer are properly 20 a torsional vibration damper constructed, in acassembled. 'I'he front end of member 32 is excordance with this invention; f ternally screw threaded as at 34 to engage the Fig. 2 is a longitudinal section through the threaded flange of a nut 36 sleeved over the forfront end of an engine crankshaft and an atward extremity of the member 24. When the Fig. 3 is a section thro h the damper on the are assembled in concentric relation as shown line 3 3 of Fig. 2; in Figs. 2 and 3, the entire space between the Fig. 4 is a fragmentary sectional view taken blades 30 and 33 and around them is iilled with on the line 4 4 of Fig. 2, disclosing the conrubber. The blades 30 and 33 do not extend struction of a bi-metallic thermostat; the full length of the cavity in the member 32, 30

.55 inner groove in the sprocket wheel and is pre- The thermostat may, however, consist of a bi- F18.5 is a fragmentary view of th'e inner and thus leaving space to be filled with rubber at outer metallic parts of the damper separated; the ends of the blades. Also the longitudinal F18. 6 is aview of a form of ,thermostat slightedges of blades 30 are spaced from the-inner wall ly different from that shown in Fig. 4; of member 32 while the longitudinal edges of 35 Fig.7 isaiongitudinal section throughaslightblades 33 are spaced from the outer wall of 35 ly different form of damper from that shown in member 24 and these spaces may be filled with Fig. 2; rubber.

Fig. 8 is a cross section on the line l-l of- The front end of member -32 is left open so Fig. 7. that a washer or annular presser plate 40 hav- 40 In the drawings, numeral Il represents the ing a diameter not greater than the greatest in- 40 crankshaft of an automobile engine, numeral I2 side diameter of the open -end of said member (Fig. 1),' the usual flywheel at the rear end of may contact with the forward face of the rubber the crankshaft, I4. a sprocket or equivalent wheel mass. for operating the timing devices, Ii, the vibra- Between Washer 40 and nu?l 36, Fig. 2 shows a 45. tion damper, i3. a cooling fan which is shown bi-metallic thermostat 42 formed as a ring which 45 as driven by a belt I3 engaging a groove in the tends to maintain even pressure upon the washer outer member ofthe damper. 40 throughout variations of temperature. 'I'he -The vibration suppressor or damper of this inthermostatic device 42 is normally curved in vention is designed as an attachment adapted to cross section as shown in Fig. 2, and is transbe applied to the front end of an automobile versely slotted by overlapping radial slots alter- 50 engine crankshaft. As shown in Fig. 2, there nately extending from opposite edges, for the is a groove 20 in the front end of crankshaft i0. purpose of relieving internal strains that might The timing sprocket wheel I4 is keyed to the prevent the metal from curving in the desired shaft as by key 22 engaging groove 20 and an manner in response to temperature changes.

in Fig.

the outer surface 'of the internal member'v 24.

rubber mounting between lit from loosening after The inner annularsurface of the flange 44 is preferably separated from the outer surface of the member 24 leaving anannular void so that the outer member 32 is supported on and joined to the member 24 by means of 'a mass of solid rubber 46, there'being no metallic contact between said two members. If desired, however, a

4iilling bushing may be fitted into the space between the inner surface of the flange 44 and the outer surface of the member 24. In any event it is desirable to coat all parts of the rubber mass with which'lubricating oil is likely to contact with a coating liquid of drying type insoluble in petroleum or its fractions. Many oil varnishes are suitable for a protective coating of this sort. The composition disclosed, in United States Patent #1,847,445 is also suitable for this purpose. Protective coating liquid of the drying or oxidizing type may be poured into space between the inner surface of ange 44 and member 2k3. This liquid will penetrate to all surfaces that can be reached by lubricating oil entering the same space.

By providing voids within the mass of the f the members 2d and 32, the use of. thermostat 52 or 42a may be dispensed with. As illustrated ln Fig-7 a washer or annular presser plate 40v bears against the iront face of the rubber mass and is in' direct contact with the inner face of the flanged nut 3b. Fig. '7 shows voids ci between the edges of the inner blades 3@ and the inner surface of man1 ber 32 and other voids 4B between the edges of the outer blades -and outer surface of member 2d. The rubber mass may, therefore, be lput under pressure by screwing up the nutSS causing the rubber mass to deform and squeeze more -or less into the voids.

The assembly, consisting of the inner and outer members 2d andai united by the rubber mass, which has been preioaded to any desired degree by screwing up-the nut 33, is assembled with the crankshaft by slipping it over the front end of the shaft as illustrated in Fig. 2 and then inserting a so-calied starting nut" such as 58 Fig. 2, and screwing up the starting nut until the rear end of the inner member 24 is stopped from fur-4. ther advance by the timing Wheel Iii. The starter nut 5c is provided with the usualhead with a ratcheted end to receive a startingv crank and with a hexagonal or other non-round cavity to engage a spanner or the likefor tightening the nut. A lock washer 52 may be interposed be- T tween the head and the front sidev of the inner ange 26 of the member 24. Pressure in an axial direction can be applied to member 24 in assembling the device, by rotating the starting nut in the proper direction; the lock washerfprevents it has been tightened. The rubber may be molded between the inner and outer members; or maybe molded to form in separate molds. ,Voids may be formed in the mass by inserting removable cores before introducing rubber into the molds.V Or separate mass is preloaded by setting up the blocks of premolded rubber may be introduced betweenthe blades.

It willv be understood that a confined mass of solid rubber tends to expand as thetemperature rises. If no space isprovided to permit deformation under pressur'e the frequency rate of the rubber rises with the temperature.

In the form ofthe invention disclosed in Fig. "I, the rubber mass is preloaded by setting. up the nut 36, which may be locked after the desired degree of pressure on the rubber has been attained. The locking may be effectedby a spot weld between the threads of nut 36 and member 32 or otherwise'. If now the temperature of the rubber increases it may deform into,voids 41 and 4l, the frequency remaining substantially the same as before.

In the form of the inv tion 'disclosed in Fig. 2, in which "a body of rubber without voids lls the space between members 24 and 32, the rubber nut 35, thereby forcing the thermostatlc ring (42 or 42a) against presser plate GIL-and plate 40 against the end-face of the mass of rubber. The thermostatic ring tends to atten as the temperature rises, and to curve as the temperature falls. all ordinary changes of temperature the body of rubber maintains substantially thev same frequency rate because the thermostat relieves pressure as the temperature goes up and increases pressure as the temperature goes down.

We claim: A

l. In a torsional vibration suppressor, an inner member provided with outward radiating blades, an outer inertia member surrounding the inner Thus, through A member, said outer member having one end open, and inward radiating blades intercalated with and 2. In a torsional vibration suppressor, an inner member provided with outward radiating blades, an outer inertia member surrounding the inner member, said outer member having external threads, an open end, and inward radiating blades intercalated with` and spaced circumferentially from the blades of the inner member; elastic rubber disposed between and extending, beyond said blades toward the open end, an annular Presser device of Iless vdiameter than the internal diameter of the outer member the said presser device bearing against the face of the rubber exposed at the open end, and means comprising a nut having a threaded flange cooperating with the thread on the outer inertia member for adjusting the presser device.

3. In a torsional'vibration suppressor, an inner member provided with outward radiating blades, an open ended outer inertia member surrounding the inner member and having inward radiating blades inter'calated with and spaced circumferenf tialh1 from the blades of the inner member; an

integral mass of velastic rubber having voids thereopen end of ist 4. In a torsional vibration suppressor, an inner member, a hollow outer inertia member surroundingthe inner member, an integral mass of elastic rubber disposed between the inner and outer member ior securing said members together, said mass of rubber having voids therein, and adjustable means for applying pressure to said rubber and holding it under pressure in order to regulate its periodicity.

5. In a torsional vibration suppressor, an inner member provided with outward radiating blades, a hollow outer inertia member surrounding the inner member, said outer member being open at one end and having inward radiating blades intercalated with and spaced circumferentially from the blades of the inner member, said blades extending longitudinally and radially of less extent than the cavity of the hollow outer member; an

integral mass of elastic rubber disposed between the inner and outer members, said rubber being disposed in the spaces between the blades and extending forward of said blades and having voids therein; a presser plate disposed against the exposed face of the rubber at the open end of the outer member, said plate being of less diameter' than the internal diameter of the outer member at its open end, and means including a nut threaded upon the outer member for applying an axially directed force to the presser plate.

6. In a torsional vibration suppressor, an inner member provided with outward radiating blades, an outer inertia member surrounding the inner member, said outer member being open at one end and having inward radiating blades intercalated with and spaced circumferentially from the blades of the limer member; solid elastic rubber disposed between the inner and outer members, said rubber filling the spaces between the members, and adjustable presser means bearing against the face of the rubber exposed at the open end of the outer inertia member. said presser means including a thermostatic device arranged to vary the pressure on the exposed face of the rubber in accordance with changes of temperature.

7. In a torsional vibration suppressor as defined in claim 6 in which the presser means includes a bi-metallic radially slitted thermostatic ring arranged to vary the pressure on the exposed face of the rubber in accordance with changes of temperature.

8. In a torsional vibration suppressor as defined in claim 6 wherein the presser means consists of a plate resting against the face of the rubber exposed at the open end of the outer inertia member, an adjustable flanged nut threaded to the end of the outer member and a bimetallic thermostatic ring disposed between the nut and the presser plate.

JOHN M. TYLER. 'I'HOMAS C.|VA.N DEGRIFT. 

